March 24, 1965 
v 
Dr. Charles A. Ely 
6159 Pahukula Place 
Honolulu, Hawaii 96821 
: 
Dear Dr. Ely: 
Kara. 
Enclosed is the partial analysis of the Blue-faced Booby date, from 
( 1 ) 
( 2 ) 
(5) 
My conclusions from the present data are as follows: 
If you want to merely make a statement about the Blue-faced Bobby 
population fluctuation on the island throughout the day, you can 
get better data more easily by merely counting the population each 
hour - compare graph Ho. 1 (total population) with graph Ho. 2 
(marked individuals). 
Whichever method chosen, the sample size (within each day) as 
stands should be large enough (lowest of 4$ marked individuals 
? at. January 17). T. <*o 
t'A-oV W<\0 <- 
\, \ kvv O 
^ V ^<2 
3 <*• w ' \ 
Lvav-<X. 
o 
The only statement that can presently be made is th* 
Blue-faced Booby population for Eure during January 
higher (95 °/o confidence) at 0800 and 1800 than it 
the daylight hours in between. 
(4) With the present data no statement can be Bade as to when the 
actual low occurs. 
<D 
( 2 ) 
( 5 ) 
If you want to make a mare definite statement about a diurnal low 
ie island population, I would offer the following suggestions: 
First, make observations like Kepler has done for 43+ consecutive 
hours to get an indication of the length of the cycle. From this 
data it appears that it my be longer than 24 hours. Analysis of 
the data is baaed on the assumption that the cycle 24 hours or less 
-c r 
The present data indicates that it will be very difficult to pin 
a low on any particular hour, but it may work out to a range of three 
or four hours. 
Increase the number of days sampled per month and the number of 
months sampled per year to the point that the sample can be 
stratified into days of like weather and periods of the year. The 
birds should further be stratified into nesting and non-nesting birds 
